Diabetes and congenital heart defects: a systematic review, meta-analysis, and modeling project.

CONTEXT: Maternal pregestational diabetes (PGDM) is a risk factor for development of congenital heart defects (CHDs). Glycemic control before pregnancy reduces the risk of CHDs. A meta-analysis was used to estimate summary ORs and mathematical modeling was used to estimate population attributable fractions (PAFs) and the annual number of CHDs in the U.S. potentially preventable by establishing glycemic control before pregnancy.

EVIDENCE ACQUISITION: A systematic search of the literature through December 2012 was conducted in 2012 and 2013. Case-control or cohort studies were included. Data were abstracted from 12 studies for a meta-analysis of all CHDs.

EVIDENCE SYNTHESIS: Summary estimates of the association between PGDM and CHDs and 95% credible intervals (95% CrIs) were developed using Bayesian random-effects meta-analyses for all CHDs and specific CHD subtypes. Posterior estimates of this association were combined with estimates of CHD prevalence to produce estimates of PAFs and annual prevented cases. Ninety-five percent uncertainty intervals (95% UIs) for estimates of the annual number of preventable cases were developed using Monte Carlo simulation. Analyses were conducted in 2013. The summary OR estimate for the association between PGDM and CHDs was 3.8 (95% CrI=3.0, 4.9). Approximately 2670 (95% UI=1795, 3795) cases of CHDs could potentially be prevented annually if all women in the U.S. with PGDM achieved glycemic control before pregnancy.

CONCLUSIONS: Estimates from this analysis suggest that preconception care of women with PGDM could have a measureable impact by reducing the number of infants born with CHDs.